/* IP tables module for matching the value of the IPv4 DSCP field * * ipt_dscp.c,v 1.3 2002/08/05 19:00:21 laforge Exp * * (C) 2002 by Harald Welte <laforge@netfilter.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */#include <linux/module.h>#include <linux/skbuff.h>#include <linux/netfilter_ipv4/ipt_dscp.h>#include <linux/netfilter_ipv4/ip_tables.h>MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");MODULE_DESCRIPTION("iptables DSCP matching module");MODULE_LICENSE("GPL");static int match(const struct sk_buff *skb, const struct net_device *in,		 const struct net_device *out, const void *matchinfo,		 int offset, int *hotdrop){	const struct ipt_dscp_info *info = matchinfo;	const struct iphdr *iph = skb->nh.iph;	u_int8_t sh_dscp = ((info->dscp << IPT_DSCP_SHIFT) & IPT_DSCP_MASK);	return ((iph->tos&IPT_DSCP_MASK) == sh_dscp) ^ info->invert;}static int checkentry(const char *tablename, const struct ipt_ip *ip,		      void *matchinfo, unsigned int matchsize,		      unsigned int hook_mask){	if (matchsize != IPT_ALIGN(sizeof(struct ipt_dscp_info)))		return 0;	return 1;}static struct ipt_match dscp_match = {	.name		= "dscp",	.match		= &match,	.checkentry	= &checkentry,	.me		= THIS_MODULE,};static int __init init(void){	return ipt_register_match(&dscp_match);}static void __exit fini(void){	ipt_unregister_match(&dscp_match);}module_init(init);module_exit(fini);